1. Field of the Invention
The present invention relates to a driving control method of a microwave oven and an apparatus thereof utilizing high frequency, and more particularly to a micorwave oven driving control method and apparatus for detecting whether the microwave oven is being operated without any food disposed in the cooking chamber.
2. Description of the Prior Art
FIG. 9 illustrates how a conventional microwave oven is operated by its driving control apparatus.
According to FIG. 9, the driving control apparatus of the microwave oven having a cooking chamber 20 comprises: a magnetron 101; a temperature sensor 102 for detecting the temperature of exhaust gas coming out of an exhausting port 107; a control unit 104 for receiving a temperature signal from the temperature sensor 102 to compare the same with a predetermined reference temperature; and a driving unit 106 for receiving a driving signal from the control unit 104 to drive the magnetron 101.
Meanwhile, there is a fan 109 for cooling the magnetron 101 and at the same time for ventilating the air of the cooking chamber 20, and reference numeral 108 reference food to be cooked, and reference numeral 22 reference a tray on which to place the food 108.
However, in the conventional microwave oven thus constructed, it is impossible to detect (or discern) whether or not there is food within the cooking chamber, thereby causing damage to the oven or causing fire to break out in the oven when the oven is operated without the presence of food, due to a user's mistake or a child's mischievous act.
In other words, when the oven is operated with no food 108 in the cooking chamber 20, the temperature sensor 102 cannot detect such an absence immediately, which causes the tray 22 in the chamber 20 to melt down or causes an interior paint and the like to catch fire, resulting in consequent damage and loss to the oven.
FIG. 10 is another embodiment of the conventional microwave oven, wherein a probe 110 is disposed in the cooking chamber 20 to thereby detect temperature of the food 108 or temperature in the cooking chamber 20.
However, a no-load (no-food) state cannot be detected even with the probe 110, whereby there is still the danger of fire and the subsequent loss therefrom.
In other words, it is not until some time (i.e., after damage occurs) that the probe 110 detects operation of the oven under no load.
Accordingly, a prior art apparatus has been disclosed to detect a no-load state in such a cooker as microwave oven utilizing high frequency.
As an apparatus for detecting the no-load state, a differential coil type weight detecting device composed of a steel core is disposed under the tray on which the food is placed along with a coil from which induction current is generated by movement of the core.
According to the device, when the food is placed on the tray, the core moves downward.
At this time, the induction current is generated to thereby enable detection of existence of the food on the tray.
This kind of device, however, has a disadvantage in that a light weight quantity of food cannot be detected accurately and the device is expensive.